Unless one of the exceptions applies or a special return is required, a foreign corporation must file Form 1120-F if, during the tax year, the corporation was engaged in a trade or business in the United States, whether or not it had U.S. source income from that trade or business, and whether or not income from such trade or business is exempt from United States tax under a tax treaty.

An individual (hereafter 'you') must file Form 1040NR if any of the following conditions apply to you.

1. You were a non-resident alien engaged in a trade or business in the United States during the tax year. You must file even if:

a. You have no income from a trade or business conducted in the United States,

b. You have no U.S. source income, or

c. Your income is exempt from U.S. tax under a tax treaty or any section of the Internal Revenue Code.

However, if you have no gross income, you do not need to complete the schedules for Form 1040NR. Instead, attach a list of the kinds of exclusions you claim and the amount of each.